A good reason to place a rear bulkhead directly behind the cockpit it to enable a T rescue (whereby another paddler simply lifts the stem of your kayak into the air and the water pours out) thus enabling you to renter a dry boat. So very much quicker than pumping. On the otherr hand I have used a large flotation bag pulled out and placed under the cockpit to empty an open boat by rocking it. Very effective. But I have not tried this in rough conditions.

People with new boats will resent having to drag your swamped boat up over their decks in order to empty it. Put in at least a rear bulkhead.

It is possible to perform a T rescue without having to have the boats touch at all while the capsised one is being emptied.